1. Field of the Invention
The present invention relates to a manufacturing method for a monolithic ceramic electronic component, and more specifically, to a method for forming a protective area at the side of internal electrodes in a monolithic ceramic electronic component.
2. Description of the Related Art
A monolithic ceramic capacitor exists as an example of a monolithic ceramic electronic component to which the present invention is directed. To manufacture a monolithic ceramic capacitor, typically, a step as illustrated in FIGS. 21A and 21B is performed. That is, a first ceramic green sheet 3 on which a first internal electrode 1 is formed, and a second ceramic green sheet 4 on which a second internal electrode 2 is formed are alternately stacked in a plurality of layers. A raw component body is obtained by this stacking step. After the raw component body is fired, first and second external electrodes are formed on opposing first and second end surfaces of the sintered component body. Thus, the first and second internal electrodes 1 and 2 led out to the first and second end surfaces are electrically connected to the first and second external electrodes, respectively, and a monolithic ceramic capacitor is completed.
In recent years, monolithic ceramic capacitors are steadily decreasing in size, while monolithic ceramic capacitors that can provide high capacitance are being desired. To meet these demands, it is effective to increase the effective area occupied by each of the internal electrodes 1 and 2 on the stacked ceramic green sheets 3 and 4, that is, the opposing area of the internal electrodes 1 and 2. To increase such an effective area, it is important to reduce the dimensions of a protective area 5 at the side and the dimensions of a protective area 6 at the end illustrated in FIGS. 21A and 21B.
However, reducing the dimensions of the protective area 6 at the end undesirably increases the risk of short-circuiting of the first external electrode and the second external electrode via either one of the internal electrodes 1 and 2. Accordingly, it is appreciated that considering the reliability of the monolithic ceramic capacitor, it is more preferable to reduce the dimensions of the protective area 5 at the side than to reduce the dimensions of the protective area 6 at the end.
An example of an effective method for reducing the dimensions of the protective area 5 at the side is described in Japanese Unexamined Patent Application Publication No. 6-349669. According to the method described in Japanese Unexamined Patent Application Publication No. 6-349669, a plurality of ceramic green sheets on which an internal electrode pattern is printed are stacked in layers and compression bonded together to prepare a mother block, and after the mother block is cut into parts of a predetermined size to extract a plurality of green chips with internal electrodes exposed on their side surface along which the mother block is cut, these green chips are held by a holder, and in this state, a side surface ceramic green sheet is affixed to the side surface of each of the green chips to thereby form the protective area at the side.
However, the technique described in Japanese Unexamined Patent Application Publication No. 6-349669 mentioned above has the following problems.
Japanese Unexamined Patent Application Publication No. 6-349669 does not describe a specific method as to how the plurality of green chips obtained by cutting the mother block are held by the holder.
In green chips obtained by cutting the mother block, a plurality of internal electrodes with the same polarity are exposed on their end surface, while all the internal electrodes, that is, a plurality of internal electrodes with different polarities are exposed on their side surface. Therefore, in handling the green chips, an unwanted short-circuit may occur between the internal electrodes with different polarities unless utmost attention is paid to the handling of their side surfaces. In particular, as stacking ceramic green sheets become thinner, the distance between the internal electrodes with different polarities becomes smaller, increasing the risk of a short-circuit. If a short circuit occurs, a short failure occurs in the case of a monolithic ceramic capacitor, for example.
Accordingly, it is important to minimize contact with the side surface of green chips. However, in Japanese Unexamined Patent Application Publication No. 6-349669, there is no suggestion of the above-mentioned problems and, therefore, there is no proposal as to a favorable method of handling the green chips obtained by cutting the mother block.
Similar problems can be encountered not only when manufacturing monolithic ceramic capacitors but also when manufacturing monolithic ceramic electronic components other than monolithic ceramic capacitors.